/*
 * Javlov - a Java toolkit for reinforcement learning with multi-agent support.
 * 
 * Copyright (c) 2009 Matthijs Snel
 * 
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package net.javlov;

import java.util.ArrayList;
import java.util.List;

public class EpisodicRewardStepStatistic implements Statistic {

	protected double reward, rewards[];
	protected int episodes, episode, step, steps[];
	protected List<EpisodeEndListener> listeners; //TODO better to put this in simulator and make statistic itself a listener
	
	public EpisodicRewardStepStatistic(int episodes) {
		this.episodes = episodes;
		listeners = new ArrayList<EpisodeEndListener>();
	}
	
	public void addEpisodeEndListener(EpisodeEndListener l) {
		listeners.add(l);
	}
	
	@Override
	public void init() {
		initListeners();
		rewards = new double[episodes];
		steps = new int[episodes];
		episode = step = 0;
		reward = 0;
	}

	@Override
	public void reset() {
		rewards[episode] = reward;
		steps[episode] = step;
		fireEpisodeEndEvent();
		episode++;
		step = 0;
		reward = 0;	
	}

	@Override
	public void update(State s, Action a, double reward) {
		this.reward += reward;
		step++;
	}
	
	public double[] getRewards() {
		return rewards;
	}
	
	public int[] getSteps() {
		return steps;
	}
	
	protected void fireEpisodeEndEvent() {
		EpisodeEndEvent e = new EpisodeEndEvent(episode, reward, step);
		for ( EpisodeEndListener l : listeners )
			l.episodeEnd(e);
	}
	
	protected void initListeners() {
		for ( EpisodeEndListener l : listeners )
			l.init();
	}
}
